Time delay in the variability of multiply lensed QSOs Q2237+030 , SDSS 1650+4251

We present new measurements of time delay in variability between the brightest lensed images of two multiply lensed QSO systems, Q2237+030 and SDSS 1650+4251. These targets have been selected from the CASTLES survey. The SDSS 1650+4251 system has reported time delay of 49.5 days on CASTLES, which we aim to confirm. The known time delay for Q2237+030 is too large to measure within a couple of months, so observations will continue throughout the next year. This data can help constrain the mass distribution of the lensing galaxies, and perhaps place new limits on possible anisotropy in the value of Hubble’s constant along the line of sight as well. Observations are made with the Towson University 0.4m telescope.